Posted
by
Zonk
on Friday July 06, 2007 @08:16PM
from the one-of-my-favorite-verses dept.

chinmay7 writes "There is an excellent selection of articles (and quite a few related scientific papers) in a special edition of Nature magazine on interpretations of the multiverse theory. 'Fifty years ago this month Hugh Everett III published his paper proposing a "relative-state formulation of quantum mechanics" — the idea subsequently described as the 'many worlds' or 'multiverse' interpretation. Its impact on science and culture continues. In celebration, a science fiction special edition of Nature on 5 July 2007 explores the symbiosis of science and sf, as exemplified by Everett's hypothesis, its birth, evolution, champions and opponents, in biology, physics, literature and beyond.'

Just what we need; the knowledge that there are an infinite amount of dupe posts in the multi-verse.

... and that another almost-me is wasting time on a Friday night posting on slashdot, while another almost-me is partying it up like there's no tomorrow (of course for trhat doppelganger, there may not be a tomorrow...)

... and that another almost-me is wasting time on a Friday night posting on slashdot, while another almost-me is partying it up like there's no tomorrow (of course for trhat doppelganger, there may not be a tomorrow...)

Funny thing is, in the almost-this other universe everyone who parties on a Friday night is a geek loser, and social people all post on Slashdot every day.

Now the only thing you gotta do, is devise a machine that lets you two swap the universes.

Greg Egan wrote a book [wikipedia.org] on that topic. Aliens were relying on non-collapsed wave functions as a part of their normal life. New instruments like the Hubble Telescope were causing mass genocide in the observable universe, which got some aliens pretty pissed off.

The premise of encasing the solar system reminds me of a book I read where earth was encased for, IIRC, a similar reason. I just googled around until I found it. It's Spin [wikipedia.org] by Robert Charles Wilson.

In the book the characters deduce that "human researchers discover a way of modifying the brain to provide conscious control over the process, allowing people to suspend wavefunction collapse at will..." However, there is at least one passage that suggests that this is not the case. What it suggests is that the book is set in a universe where each of these improbable events just happen, and the characters (being in this special universe) infer that they are causing these improbable events.As a physicist, Gr

Going beyond the semantic issue, the GP seemed to be implying that consciousness is something special, some unknown part of nature.

However, suppose that you ask a person if they are sane. Should you believe their answer? The only means you have to evaluate the experience of your own consciousness is your own consciousness itself. If your consciousness wasn't some supernatural thing but instead was a little program in your brain to fool you into protecting your existence above all else by creating the illusion of being something special and supernatural, you wouldn't be able to tell the difference.

Now consider everything that we know about reality. Does the universe work more like a precise machine or more like some transcendental mystical metaphysical drug hallucination? Consider everything we know about the mechanics of the brain. It is organized a lot like and its components are a lot like a computer. Is this a description of a ghost trap or of a computational device?

Qualia [philosophypages.com] refers to the subjective features of consciousness, which are not reducible to a naturalistic explanation. In the philosophy of mind (oooh, scary, not hard sciences!) it's used to refer to something that physicalists and reductive materialists have a hard time explaining. Myself, I'm a supervenient physicalist, meaning I think that consciousness supervenes on the physical, but cannot be explained by, reference to physical laws alone. Consciousness, and the study of it, inhabits its own scientific sph

Myself, I'm a supervenient physicalist, meaning I think that consciousness supervenes on the physical, but cannot be explained by, reference to physical laws alone. Consciousness, and the study of it, inhabits its own scientific sphere that is not reducible to physics or biology or some other "basic" science.

Well, good for you. Of course, your explanation above is the exact equivalent of someone telling me that they believe in God and thumping "the good book", or that they believe in magic. You may belie

No, it isn't. Much of philosophy is every bit as rigorous as hard science (though, I will admit, some is not); they (we, actually) are just working with different axioms and different data sets. My personal work revolves around uniting the three perspectives (computation, physics, and metaphysics) through a zero-player game model, much like cellular automata systems. Folks like Wolfram, et. al. give us a bad name. Popper's three-worlds hypothesis or Whitehead's Process and Reality might give you a taste o

Much of philosophy is every bit as rigorous as hard science (though, I will admit, some is not); they (we, actually) are just working with different axioms and different data sets.

Even if you do come up with a thoroughly rigorous and internally consistent philosophy of things beyond observable reality, what of it? There is no way to know if it's right, because it can't be tested. There are conceptually an infinite number of such philosophies, so the probability of any one of them being the correct descri

Touche, didn't know the connection. However it still IMHO clashes with the idea that consiousness is "outside science" unless you mean that it's ulimately unkowable but lets not get into teapots orbiting the sun - suffice to say I think Penrose should have stuck to maths.

I can't be bothered typing out my bookself but I found you don't have to be god to proclaim "I am".

......It is organized a lot like and its components are a lot like a computer.........However, even a computer has this thing called software, an immaterial product of mind. No matter how minutely you examine the physical hardware of a computer, you learn little or nothing about its software until you turn it on.

Jesus in particular and the Bible in general mentions the existence of another dimension, that of the spirit. It is in effect another universe, where different rules apply. He called that universe "

The bible is only sacred to those who believe in the divinity of its writers and protagonists. If I were to write my own bible, would you use it as screed for defining the Universe? No, because you wouldn't believe in my divinity. The problem, therefore, with attempting to argue such issues lies with the personal beliefs of the audience. What you hold sacred, the majority of humanity regards as a curiosity.Biblical mysticism first requires that a person believes in the supernatural. This in itself is an unf

.....would you use it as screed for defining the Universe......I never did and the Bible doesn't either. Both science and the Bible give hints that there are other dimensions. You did not read the last sentence of what I wrote before. Of course you can believe or not, but that is all. Nothing can be proven.

(...Want to prove that Jesus rose from the dead?.....)

I do believe that he did, based on the testimony of multiple witnesses. We humans tend to declare that which we do not understand as "mystical" or "su

......If you examine the hardware minutely, you can notice the patterns on the media.........With enough effort, you could determine patterns, but not necessarily the meaning or message of these. For centuries, scholars could discern the patterns engraved in the ancient stones of Egyptian monuments, but the meaning of these had been lost until the "Rosetta Stone" was found and used in 1822, somewhat like a cryptographic key to make sense of the ancient inscriptions. Because we know the ASCII code, we have

Not only is there a reason for me to believe that my own consciousness exists, but (according to Descartes) it is the only thing I can be certain exists.* I can't posit that someone/something is lying to me about the existence of my own consciousness because without it there is no me to be lying to in the first place. I do consider it a fairly tiny and useful leap of faith to believe in the objective reality I observe, though.

That being said, I don't buy that consciousness is required for a collapse in

For that sentence to have any meaning whatsoever there has to be a "witness" in the first place, meaning consciousness. Whether it all actually comes down to programming or not is completely irrelevant. No matter how you slice it, that the tiny subset of nature that is us is able to comprehend nature itself is pretty remarkable.

For that sentence to have any meaning whatsoever there has to be a "witness" in the first place, meaning consciousness.

At this stage, we get bogged down in semantics.

Whether it all actually comes down to programming or not is completely irrelevant.

Irrelevant or not, this is the subject at issue in the entire thread. Most people seem to believe that their consciousness demonstrates that they are special and have a supernatural soul that will have an afterlife. However, there's no good reason to believe t

The only semantics involved is the definition of "consciousness." And if you're going to claim that a thing does not exist, it's kind of important to pin down what people mean by that thing in the first place. "Consciousness" is most commonly thought of as awareness, especially of one's own existence but also of one's surroundings. I don't think it's too big of a leap to consider this awareness to be equivalent to the self.

When something is measured, it collapses it... What causes the collapse?
Perhaps consciousness?
No. It's just that once you've measured where something is, the probability of it being somewhere else is drastically reduced for a while.
What's the probability that I left my keys in the kitchen instead of the bedroom? Let's say 50%.
"Oh," a friend says, "I just saw them in the bedroom." so what does that probability become? 0%.
It was measurement, not some mystic force, which reduced the area in which my keys are most likely to be found. It's no different with quantum mechanics.

Except that I've never had the probable state of my keys being in the kitchen destructively interfere with the probable state of my keys being left in my bedroom to make my keys more likely to be on the key ring...:-)

Generally at the quantum level, a measurement or observation is when you bounce a particle (usually a photon) off another particle.It's similar to how you see things. Light bounces off of a thing, and that light bouncing into your eye is how to observe and measure things. Just lower the scale to a single photon of light (or even a smaller particle) and youre set.

The reason you can't measure all the details of a particle at this level is because when the photon you bounce off it actually hits the particle

The reason you can't measure all the details of a particle at the same time is NOT because photons bounce off of it and disturb it. The reason you can't measure all of the details of a particle at the same time is because that is JUST THE WAY IT IS. It has nothing to do with interference from other particles. There is no "reason" for it. No one knows why it works that way. It's called "complementarity", and it's the fundamental quantum mystery.

The Heisenberg uncertainty principle gives a lower bound on the product of the standard deviations of position and momentum for a system, implying that it is impossible to have a particle that has an arbitrarily well-defined position and momentum simultaneously.

The parent poster's analogy is correct in the sense that taking measurements are massively disruptive to a particle. Like measuring where a pool ball is in the dark by throwing things at it. You can know the position almost exactly of a particle at any given time, but then you can't know where it is headed next since the momentum is uncertain.The thing he didn't elaborate on was that until that physical interaction (and after it), the particle exists like a wave. It has everything to do with interference

I'm not a physicist but at least from what I've read that's a rather common misconception.

It is the act of measurement itself, not the interaction of the particles that causes changes we see in the particles. The collapse of a wave function is different from anything that we have in the macroscopic universe, it simply does not happen in every day life to an extent that we can view it.

In the many worlds interpretation of quantum mechanics the wavefunction does not collapse (that is the copenhagen interpretation).Rather, all the *possible* outcomes of a quantum measurement do happen: each one in a different universe.When you measure one particular outcome, that means that you are in the particular universe where you measure that outcome: by definition.A measurement consists in an event that translates "quantum information" into "classical information": quantum information is very complex

in the MWI there is no collapse. That's what distinguishes it from other interpretations of QM (e.g. the Copenhagen Interpretation). Instead the MWI proposes that any time something happens, a new branch of the multiverse is created (one branch the photon is spin up, the other branch, spin down.) Yes, that's a REAL lot of branches.

When something is measured, it collapses it... What causes the collapse?

No in the MWI the wavefunction does NOT collpse. This is the whole point of the MWI, in the Copenhagen interpretation the wave function collapses on a measurement to a single state. In the MWI a measurement splits the world into two different states there is no collpse of the wavefunction.

The Copenhagen interpretation abolishes physical reality and brings in the idealist concept of a conscious observer collapsing the wavefunction. The MWI restores physical reality in quantum mechanics.

The CI supporters would say the MWI didn't explain why we don't see the off diagonal mixed states. But the modern approach to the measurement problems in MWI uses the concept of decoherence which is the interaction of the isolated quantum states with the macro environment. It has been shown that the mixed states are destroyed by interference when decoherence from interaction with the environment occurs. Thus in this experiment the world is split into two, one where the cat is alive and one where it is dead.

The decoherence approach in conjunction with the MWI abolishes the necessity of observers and restores the independent physical reality abolished the the CI. The proliferation of many worlds is the price we have to pay for physical reality and the unitary evolution of the wavefunction.

The Copenhagen Interpretation puts a magical significance on "measurement" that boggles the mind. It' not just photons interacting with the system, it's those photons being perceived by a mind. What's special about minds? Sssshhhh, don't ask that question.

This insistence upon putting the mind (particularly the human mind) at the center of the quantum universe reminds me of the insistence of the Medieval Church upon putting the Earth at the center of the Universe. I'm p

When something is measured, it collapses it... What causes the collapse?

There is no such thing as "wavefunction collapse".

Apart from the second law of thermodynamics (which, it would be fair to say, we don't really understand), all of the laws of physics are time-symmetric. In quantum theory, causality works backwards in time just as well as it does forwards, and that includes interactions that leak quantum information.

What does consciousness have to do with it?? Do you think physicists are just sitting around watching photons and eyeballing the measurements? No, obviously they have computers and lab equipment that is recording that information, and will continue to do so whether a conscious person looks at it or not.

The collapse of the wavefunction is caused by interaction with other particles. After the interaction, the particle has a new modified wavefunction.

The many-worlds hypothesis does have some serious problems, such as how a universe with probability p and one with probability -p cancel each other out. (The branching would have to happen "after" the cancellation.)

It seems to me that we are hitting the limit of what we can understand through measurement. At a small enough scale, measurement seems to break down, and then we get probabilities, and phenomena that are open to mathematical interpretation.

So, being 'inside' the universe and taking its measurements from the inside only gets us so far. Beyond that, we have theories about the nature of the universe, but they can't be shown to be true or untrue. There are theories that are certainly untrue, but there are al

I disagree. In 1900, the amounts of power required to learn something useful were on the order of Watts. Anybody (even in an area without electricity) could sit and do meaningful research if they had the inclination and they didn't have to work for a living. People like Thomas Edison, Nikolai Tesla, James Clark Maxwell, could be mad scientists in a way that just isn't possible today. By the 1940's the amount of power was up to Megawatts, and fundamental research already required major industrial scale i

It's not the math, it's the explanatory power. Read The Fabric Of Reality [amazon.com] by Deutsch, for instance. The Copenhagen Interpretation [wikipedia.org] says "... and then a miracle happens" (meaning the faster-than-light collapse of the wavefunction). The MWI [wikipedia.org] says there's nothing faster-than-light about it; there's just no collapse.

I've observed many times that I "should have" died. It struck me that, perhaps, I did die in an alternate universe, but I (whatever I "is") continue on in at least one of the multiverses. In those multiverses in which "I" experience the death of a close friend or family member... well... that just is how it goes. But they, too, continue in an instance of the multiverse. Perhaps I do not.

I had a friend and former roommate who was in an apartment fire. He was sleeping in bed when his cat woke him up by clawing at his face. He startled awake and saw that the ceiling was covered in flames. He escaped, certain that he was moments away from death.

Luckily he made it out alive. But he suffered severe PTSD for a few years afterwards. He would just be walking to the grocery store and be suddenly struck with the terrifying reality that he wasn't walking to the store at all -- this was the final hallucination of his mind moments before he perished in the apartment fire. Instead of his past flashing before his eyes, this was his mind's final, desperate attempt to comfort itself, by creating a reality where he lived out the rest of his life.

I try not to think about it because it's creepy. If I really start to think about it I get terrified.

What do your friend's mental problems have to do with physics? I know it is late on Friday night, but I'm not nearly drunk enough to believe your anecdote has anything to do with some sort of tacky, sci-fi, interdimensional communication.

In fact, the ONLY lessons to be learned from your story are1) Check your smoke detector batteries, dumbass!2) Get a cat.

In fact, the ONLY lessons to be learned from your story are1) Check your smoke detector batteries, dumbass!2) Get a cat.

So... What if in universe B you didn't check the batteries because you flipped a coin that came up heads... Or got a dog instead of a cat because you killed the original cat in some sort of weird science experiment.

Conservation of momentum in teleportation plays an important role in The Witling [wikipedia.org] by Vernor Vinge. Also conservation of energy features prominently in some of Larry Niven's teleportation stories, particularly The Alibi Machine. Technical stupidities in TV scripts are far too numerous to worry about.

Note that this is not a very exciting kind of immortality. Especially since a goodly number of worldlines coming from here will produce computronium [wikipedia.org]. At least some of which will simulate you, yes you personally for an unspeakable amount of subjective time (possibly infinite if even one non-zero probability path leads to that outcome), during which you will in some cases experience what can only be described as "as close to a literal heaven as you can get", and in other cases "as close to a literal hell as you can get", and the full range of things in between. If Quantum immortality is "true", there are things worse than death, and we will more or less all get to experience them on some worldline.

Note further that it is not meaningful to wish that "you" will end up in one of the good cases; if QI is true, all cases lie in your future equally. "You" will end up in the good and the bad and the inbetween, all at once. Perhaps some people consider this a form of escapism, but it is also fairly horrifying if you follow the implications out beyond "In some very real sense, I can not experience death."

Life is suffering. If the mutliverse is true, then absolute hell really does exist in one instance of a Universe. If QI is true, is there ever really a way to escape 'reality'? Does everyone experience every form of existence for eternity? or instead do some of us go into loops of existence, and never escape the loop? Can we direct our path to a desirable loop?

Some forms of Buddhism teach something very similar to QI, except that Nirvana is the end of all suf

Life is suffering. If the mutliverse is true, then absolute hell really does exist in one instance of a Universe. If QI is true, is there ever really a way to escape 'reality'? Does everyone experience every form of existence for eternity? or instead do some of us go into loops of existence, and never escape the loop? Can we direct our path to a desirable loop?

Your willpower and intent allow you to chart your own course through reality. Hell is a very small and abstract concept, a creation of this world.

Yup, that's a well-known position, called "Quantum Suicide" or "Quantum Theory of Immortality". You shoot yourself, and in most universes you die, but in a very few the gun jams, the bullet is struck by lightning before it hits, etc. In any case, you always survive in at least a few universes (there are infinitely many), so you never "experience your own death" as it were. The dead ones are dead, the live ones think "wow, I made it!" Unfortunately it's far more likely you survive with terrible pain than

Well what if there's no universe where the gun jams? All those universes were ruled out by other events?

Sure most of the other Yous who decided not to do such a stupid thing live merrily on in their Many Worlds, but the Yous who decided to Quantum Suicide might find out the hard way that "the wrong turn ends here".

Why should MWI mean that ALL chosen paths will avoid 100% Darkness? To me that's like saying the two slit experiment doesn't have destructive interference.

One of the tenets of the MWI is that everything that is physically possible (i.e. is consistent with the evolution of the Schroedinger Wave Equation, or similarly, consistent with physical law) happens in some universes. Maybe with extremely low probability, indeed (10^-30 or even lower), but nonetheless it happens somewhere. Things like all the coffee molecules in the cup simultaneously moving upward and the coffee appearing to jump out of the cup, for instance. You can compute these probabilities: p(on

've observed many times that I "should have" died. It struck me that, perhaps, I did die in an alternate universe, but I (whatever I "is") continue on in at least one of the multiverses. In those multiverses in which "I" experience the death of a close friend or family member... well... that just is how it goes. But they, too, continue in an instance of the multiverse. Perhaps I do not.

Probably the most interesting practical question is what percentage of futures include all our lost family members and f

Zzzzzzz... O. Sorry. Did you say something?Talk about nitpicking critiques, dude. ("Dude", because I've never met a chick with such a need to strain gnats.)

"Should have died" => colloquialism for "surviving a situation in which I had a high chance of dying." Does that make you feel superior, now?

As to the charge that I was espousing philosophy... you are incredibly dense. I said, explicitly, that I was referring to "personal experience" regarding what I subjectively "observed." I made no philosophical or

The multiverse hypothesis is an ancient idea. I remember reading about a poetic image used in Hinduism to describe it: that of "Shiva's Necklace". It's said that the god Shiva, which together with Vishnu and Brahma form the (main) Hinduist Trinity, the Trimurti, wears around his neck an infinitely long necklace with an infinite number of beads. Each bead is a full universe, ours being just one among them, and Earth with us just an infinitesimal aspect of that single bead.

It would be nice if scientists, when talking to non-scientists, drafted lively images like this one. IMHO, it would go a long way in bridging the gap between them and "normal" people, who don't think in terms of numbers and mathematical concepts.

Many scientists do come up with such metaphors for their work. There are two related problems with this, though: first, the metaphors just aren't that good -- most of the time it's simply impossible to give an accurate description of the problem without the math -- and second, non-scientists will refuse to put the effort into understanding the math, take the metaphor, and think they understand the whole thing. Especially when you're talking about physics, but really in most scientific fields, it is not p

Anyone who can't explain something in plain English doesn't understand it themselves.

English is a very good language for describing a lot of things; but math is also a language, and sometimes (in the sciences, often) it's a much better one for describing certain things. You can often write the mathematical terms out rather than using symbols, of course, but honestly, when you're dealing with inherently mathematical subjects such as physics, that's as close as you can come without losing a lot of informatio

Shiva, which together with Vishnu and Brahma form the (main) Hinduist Trinity, the Trimurti, wears around his neck an infinitely long necklace with an infinite number of beads. Each bead is a full universe, ours being just one among them, and Earth with us just an infinitesimal aspect of that single bead.

It would be nice if scientists, when talking to non-scientists, drafted lively images like this one.

So, you are saying that science should invent religion in order to explain the world?What an original idea!

In celebration, a science fiction special edition of Nature on 5 July 2007 explores the symbiosis of science and sf, as exemplified by Everett's hypothesis, its birth, evolution, champions and opponents, in biology, physics, literature and beyond.'

Wow, an entire thread on the multiverse hypothesis, and no one's mentioned Noein [anidb.info] yet? By far one of the best anime programs of the past couple of years, Noein depicts a conflict between alternative universes that comes to involve a group of middle-school kids in Japan. The producers actually try to explain some of the science involved, including a cute scene with Schrodinger's cat. One of the most experimental animes I've ever watched, and I've watched quite a few. The style of animation is rather unusu

Quantum computing is equally bunk since it is based on the idea that a quantum property can have multiple states simultaneously, that is, when nobody is looking. ahahaha... Reminds me of the kid I knew who insisted that he could jump as high as a tall building but only when nobody was looking. Whatever happen to empiricism? Talk about pseudoscience! Everett, Schrodinger (and his stupid cat) and that lunatic David Deutsch are crackpots of the worst kinds. Only physicists can get away with such quackery. They should all be stripped naked, tarred, feathered and paraded down Fifth Avenue in New York as an example to undergraduates. ahahaha...

Sorry, your computer now refuses to work because it no longer obeys quantum mechanics. The electrons are just stuck at the N-P junctions and nothing happens because they're all in a fully defined position with no way of jumping across it at the energy levels they have. Bump the energy up, and they behave classically and just burn their way through without any of the nice semiconductor properties that make computation with them possible.

On the upside, now you'll have a lot more time to tar and feather the quacks who made your nonfunctional computer!

Physics is weird. Perceptions are inaccurate and experiments have shown that. You're saying quantum mechanics is wrong because it disagrees with your perceptions. But your perceptions, those are what are wrong.

Probably the best use for all the world's nuclear weapons would be to situate them around all the cities on earth so that everything on earth fell within a very, very high percentage kill zone. Then give everyone a very reliable detonator. Everyone suddenly has a much higher probability of being in a perfect Utopian universe.

If by "perfect Utopian universe" you mean dead, then yes. Somebody's going to push that button.But lets assume for argument sake that nobody does. People will quickly learn that nobody will push their button, and nobody will seriously care that others have them. We will be in much the same place we are right now.

That's the problem with the current (and former) arms race. We weren't willing to "push the button" (meaning nuke Russia), and Russia wasn't either. Both countries were reduced to non-nuclear m

Ahh, that explains it. I didn't get that interpretation because I see the odds of that possible existance == 0.Even so, the middle of my post stands. We all would simply come to accept that nobody will push the button. Life would otherwise continue almost completely uninterrupted. It would not end war, or crime, or poverty, etc.

And if we were each to hit the button when we saw something un-Utopian, then it would only truly drive the possibility to zero. (I'm postulating that some things are deterministi

And if we were each to hit the button when we saw something un-Utopian, then it would only truly drive the possibility to zero. (I'm postulating that some things are deterministic, at least, even if their symptoms are not always.)

There's really no way to drive the probability to zero. In the worst case, the nukes just fail to kill everyone and they survive in a ruined world. In the best case, they just fail to work at all. I suppose it's a matter of degree; the closer society approached to utopia, the mo

I rather like Buddhism, but I have found that there is no need to label one's belief as 'Buddhist', or anything else for that matter. The operating system of the universe does not care what you call it or who has labeled it in the past. There are elements of Buddhist thinking which don't ring true for me, so who needs 'em? Others make a lot of sense. --And there are ideas from other practices which also make a lot of sense. And since they